The present invention relates to a low pressure evaporation concentrating apparatus for photograph process waste disposal, and more particularly concerns a low pressure evaporation concentrating apparatus for photographic process waste disposal suitable for processing of photographic process waste liquid generated in the development process of photographic sensitizing materials by an automatic developing machine in it or in the vicinity of it without collecting dealers.
Also, the present invention relates to an improved method and system for increasing a concentrating speed and a thermal efficiency in evaporating and concentrating the photographic process waste liquid.
For monochrome sensitizing materials, in general, photographic process of halogenated photographic sensitizing materials is carried out by development, fixing, and water washing. For color sensitizing materials, it is carried out by combined steps using process solutions having one or two features of color development, bleaching fixing (or bleaching and fixing), water washing, and stabilization.
In addition, the photographic process for mass sensitizing materials has to have the components consumed in the process supplied. It has to remove components such as bromide ions in the developing solution and complex silver salt, dissolved in the process solution or concentrated by evaporation to keep the components constant and to maintain the performance of the process solution. For the purpose, the process solution has to be replenished, and parts of the process solution have to be discarded to remove the components concentrated in the photographic process.
Recent photographic developing systems have been improved so that the supply solutions, including the washing water, can be reduced considerably for environmental and economic reasons. The photographic process waste liquid, however, has been led from a process tank of the automatic developing machine through a waste liquid pipe, diluted with the waste washing water or cooling water for the automatic developing machine or the like, and discharged into sewers.
However, though the washing water and cooling water can be discarded to the sewers or rivers, with recent strengthened environmental pollution restriction rules, it is substantially impossible to discard the photographic process solutions such as the developing solution, fixing solution, color developing solution, bleaching fixing solution (or bleaching solution and fixing solution), and stabilizing solution.
For the reason, photographic process traders have to pay to have the waste liquid collected by special waste process dealers. Alternately, they install a pollution preventive facility.
However, the entrustment to the waste process dealers has a disadvantage that it needs considerable space to reserve the waste liquid. Also, the costs are very high. The pollution preventive facility also has a disadvantage that it is very expensive in initial cost. It needs very large space for its maintenance.
There have been many processes proposed for environmental pollution prevention to reduce the pollution extent of photographic process waste disposal. They include the activated sludge processes proposed in the Japanese Patent Examined Publication Nos. 12943-1976 and 7952-1976, the evaporation processes proposed in the Japanese Patent Publication Open to Public Inspection Nos. 89437-1974 and 56-33996, the electrolytic oxidation processes proposed in the Japanese Patent Publication Open to Public Inspection Nos. 84462-1973 and 119458-1973, the Japanese Patent Examined Publication No. 43478-1978, and Japanese Patent Publication Open to Public Inspection No. 119457-1974, the ion exchange processes proposed in the Japanese Patent Examined Publication 37704-1976, the Japanese Patent Publication Open to Public Inspection No. 383-1978, and the Japanese Patent Publication Open to Public Inspection No. 53-43271, the reverse osmotic processes proposed in the Japanese Patent Publication Open to Public Inspection No. 22463-1975, the chemical processes proposed in the Japanese Patent Publication Open to Public Inspection No. 64257-1974, the Japanese Patent Examined Publication No. 37396-1982, the Japanese Patent Publication Open to Public Inspection Nos. 12152-1978, 49-58833, 53-63763, and the Japanese Patent Examined Publication No. 37395-1982. These processes mentioned above are not sufficient for preventing environmental pollution.
On the ocher hand, there has been proposed a waterless automatic developing machine having no piping for feeding fresh water and draining waste water and having a stabilizing process in place of water washing. Recently, it is being popularly used in connection with restriction of water resource, increased water feed and drainage cost, simplified process, and operational easiness around it. For such a process, it is desired to omit the cooling water for controlling the temperature of the process solutions.
The photographic process having absolutely no washing water and cooling water has very high pollution potential as it is not diluted with water as compared with the one having the waste liquid drained from the automatic developing machine on the other hand, it is distinguished by a small amount of waste liquid. With little waste liquid, piping for feeding water and draining the waste liquid can be omitted outside the machine. The features solved the disadvantages of the conventional automatic developing machine that the piping is hard to move after installation, the operating space becomes too narrow, the installation cost is too high, and high energy cost for feeding warm water is needed. The improved machine therefore had a very high advantage that it could be made so compact and simple that it can be used as office machine.
However, on the other hand, the waste liquid has a very high pollution capability so that it cannot be discharged into sewers and rivers as well in view of recent environmental pollution restrictions. The quantity of waste liquid in such a photographic process is relatively small, but amounts to 10 liters a day in a small color process laboratory.
Thus, the waste liquid would be generally collected by the waste liquid collecting dealers, who make a second and third treating of it to avoid pollution. The price for collection of the waste liquid becomes higher year by year. The small laboratories cannot easily have the waste liquid collected as its collection efficiency is too low, resulting in abundance of the waste liquid in the shops.
In order to solve these problems, it has been proposed to heat the photographic process waste liquid to evaporate the moisture to dry or solidify it so that the photographic process waste disposal can be made in the mini laboratory shops. Such a method was disclosed, for example, in the Japanese Utility Model Application Laid-Open No. 70841-1985.
With investigation of the inventors, they found that if the photographic process waste liquid is evaporated, this generates harmful or very offensive gases, such as sulfurous acid gas, hydrogen sulfide, and ammonium gas. It was found that the gases were generated because the ammonium thiosulfate and sulfites, such as ammonium salts, sodium salts, or potassium salts, which are often used for the fixing solution and bleaching fixing solution, are decomposed at a high temperature. In the evaporation process, further, the moisture in the photographic process waste liquid is evaporated to vapor to expand its volume. This causes the pressure in the evaporation pot to increase. The increased pressure causes the harmful or offensive gases to leak out of the evaporation apparatus. This is very undesirable for operational environment.
In order to solve such problems as mentioned above, the Japanese Utility Model Application Laid-Open No. 70841-1985 has disclosed a method that an evaporation process apparatus has an exhausted gas process section having activated charcoal or the like provided at an exhausting pipe thereof.
However, this method has the serious disadvantage that the vapor of a large amount of moisture from the photographic process waste liquid becomes dew or condensed water at the exhaust gas process section, and the moisture covers the gas absorbing agent and thus instantaneously loses its gas absorbing capability. So, it cannot be used for practical application yet.
In order to overcome such difficulties as mentioned above, the inventors have previously proposed a photographic process waste liquid treating method and apparatus that when the photographic process waste liquid is evaporated, the apparatus has a cooling condensation unit provided to condense the vapor generated in evaporation, to properly treat the water condensed in cooling and to discharge, and to properly treat non-condensed components.
However, the inventors found the following problems in the proposal mentioned above. The vapor generated in the evaporation process can be usually condensed by the cooling condensation unit. If the cooling condensation efficiency is too low, however, a ratio of the vapor that is not condensed but discharged becomes high. Even if it is absorbed with the activated charcoal, a ratio of the harmful and offensive gases discharged also becomes high. The water condensed by the cooling condensation unit, also, causes pollution even if absorbed by the activated charcoal. As it is high in the pollution capability, it cannot be often discharged to sewers directly.
As a mini laboratory shop is limited in the space, the offensive smell generated through the photographic solution process becomes a serious problem. It is also a problem that the waste liquid process apparatus itself occupies the limited place. Its expensive price and high running cost further raise a serious problem.
Thus, it has been requested to have a novel waste liquid process apparatus that can process the photographic process waste liquid at a high concentrating speed without generating harmful and offensive gases, being of compact form, available at inexpensive price and capable of operating at a low running cost.
In order to solve such problems, the inventors have proposed methods such as described in Japanese Patent Publication O.P.I. No. 151301/1988 and the like that are available to reduce the offensive smell generated from the photographic process waste liquid, to condense the waste liquid in a relatively secure way, and to make its disposal easy. It uses a low-pressure method in which the gas pressure in a column is lowered to evaporate the waste liquid at a relatively low temperature, but the temperature of the exhaust vapor remains high. It therefore still has the disadvantage of components of offensive smell mixing in the exhaust vapor.
For this reason, the exhaust vapor also should be cooled to condense it. The offensive smell can be reduced together with the exhaust vapor so that the offensive odor can be further prevented. However, with both a heating unit and a cooling unit, the apparatus becomes large, and the installation cost becomes high.
In view of solving the problems mentioned above, it is the first object of the present invention to provide a low pressure evaporation concentrating apparatus for photographic process waste disposal without generation of offensive smell which is achieved in a compact form at low cost and has high efficiency.
As described previously, the photographic process waste liquid has to be evaporated and concentrated in an on-demand way in a vicinity of the automatic developing machine. It is however not a good method to use a conventional electric heater for evaporation as it consumes high power. In order to solve this, the inventors used a heat pump that has been proposed in the Japanese Patent Publication Open to Public Inspection No. 151301-1988. The heat pump was provided for a heating section to evaporate and to a cooling section to cool the generated vapor and gases. It was successfully achieved to reduce the consumed power to lower than 50%.
However, a photographic laboratory does not only consume a large amount of power for evaporating and concentrating the photographic process waste liquid, but also consumes a great amount of power for temperature controlling of the process solutions in the automatic developing machine and for heating or cooling in a drying section.
By all accounts, it is further requested to reduce the heating and cooling powers. In particular, if power higher than 30 A is needed, it also costs for wiring the power line.
In view of the foregoing, it is the second object of the present invention to provide a low pressure evaporation concentrating method and apparatus for photographic process waste disposal that can further increase the heat efficiency and improve the treat capability.